Thursday’s two front pages of the Sun and its sister paper in Scotland
Photograph: .

The Sun has endorsed the Conservatives to win the general election but its Scottish edition is backing the Scottish National party.

The Sun claims David Cameron is the right choice to stop the SNP running the country even though its sister paper in Scotland is supporting Nicola Sturgeon’s party.

The pro-Tory edition had a picture of Cameron’s face on a baby in an apparent reference to the royal birth, saying: “It’s a Tory.” The pro-SNP edition shows Sturgeon mocked up as Princess Leia from Star Wars, with the headline: “Stur Wars: May the 7th be with you: why it’s time to vote SNP.”

The differing endorsements of the two regional editions of the Sun is likely to fuel Labour claims of an “unholy alliance” between the Conservatives and SNP against Miliband. However, Labour had no immediate response.

Polling suggests Labour could be almost wiped out in Scotland by the SNP, while the Tories and Labour are neck-and-neck in the rest of the country.

The move comes just days after Sun and Times owner Rupert Murdoch predicted Cameron would face the axe if he failed to win a majority against Miliband after not securing one previously against Gordon Brown.

There have been reports that Murdoch has been putting pressure on Sun journalists to lean even more in favour of the Conservatives in their reporting.

Earlier on Wednesday, Miliband said in his interview with comedian Russell Brand that he had already stood up to Murdoch over phone hacking and would look at reviewing the rules of media ownership if he becomes prime minister.